The present invention relates to dual stereomicroscopes, particularly for use in microsurgery.
Operating microscopes are well known in the art and are used in eye surgery and in plastic reconstruction surgery. During such surgery it is desirable to provide simultaneously two independent stereomicroscopes, one for the surgeon and one for an assistant. The surgeon and assistant should be able to see the same operating field with as nearly the same view as possible and with equal and maximum lighting without distortion or degradation due to differing optics in their respective microscopes. It is also desirable that each stereomicroscope have an independent zoom magnification capability since surgeon and assistant, at different phases of an operation, would need different magnification and field coverage to better suit their different tasks.
Further, it is desirable to provide for a separate microscope accessary port for use with a camera or video recorder which port has visual access to the operating field without replacing one of the microscopes.
In the Riedel patent, U.S. Pat. No. 3,170,983, two stereomicroscopes opposite one another are combined. Each stereomicroscope is complete including its own objective lens, but, to combine the two, it is necessary to add a pentagonal prism symmetrically located between the separate microscopes. See also Littman's patent, U.S. Pat. No. 3,186,300, where two stereomicroscopes, including objective lenses, also are combined with an arrangement of reflectors positioned symmetrically between the objective lenses.
In the Peyman et al patent, U.S. Pat. No. 4,138,191, a dual stereo viewing operating microscope which shares a common objective lens is provided. The two pairs of stereo tubes 21, 22 and 23, 24 intersect perpendicular planes i.e., the viewers using the microscopes are at right angles to one another, a configuration suitable for eye surgery but not for plastic reconstruction surgery. Although Peyman states that the lens cartridge 25 may comprise a plurality of variable magnification lens combinations or may be a "zoom" type lens structure to provide infinitely variable magnification, no structure such as gearing, motor, etc. is shown to provide independent zoom capability for both stereomicroscopes simultaneously.
While Peyman discloses the capability to add a camera to the microscope with access to the operating field, the camera 28 can only be effective with the use of prism 29 which switches the camera in by switching the stereoeyepieces 43 and 44 out. Hence, if the camera is to be used, the stereomicroscope is no longer a dual stereomicroscope.
In U.S. Pat. No. 4,341,435 (Lang et al), a stereoscopic microscope is disclosed that provides for multiple observation, so that surgical operations or other events may be observed simultaneously by two observers, or by one observer and a television apparatus. The two stereoeyepieces share a common light path, the viewing paths of the two pairs of stereo eyepieces intersect planes at right angles to one another, and, if a TV apparatus or camera is to be employed, the device no longer has a dual stereomicroscope capability.
In U.S. Pat. No. 4,605,287, also issued in the name of Lang et al, a surgical microscope for two surgeons is disclosed that uses beam splitting to effect the dual stereo capability.